An oscillator is a core device in a microwave transceiver. Moreover, phase noise and high stability of the signal source or a local source play a decisive role in the entire microwave system, especially in a low cost dielectric resonator oscillator (DRO).
In a DRO, the permitted range of operating frequencies is critical throughout an entire temperature range. The permitted range of operating frequencies can be understood as signal bandwidth (MHz) plus temperature drift (MHz). Accordingly, if the temperature drift is reduced, then the permitted range of operating frequencies can be reduced accordingly.
Some known systems and methods to reduce temperature drift include applying a thermistor and changing the voltage in a bias circuit for temperature and frequency compensation. However, these systems and methods introduce an additional device (the thermistor), introduce unexpected noise, increase the area of a printed circuit board (PCB), and increase the cost of the device while only providing only a small compensation range.
Other known systems and methods to reduce temperature drift include reducing the temperature coefficient of a dielectric resonator (DR), for example, with the use of a low temperature coefficient, high stability, and high performance DR to achieve a small drift. However, these systems and methods require higher quality materials, which increase the cost of the device. Furthermore, these systems and methods can only stabilize frequency, but cannot compensate for frequency drift.
In view of the above, there is a continuing, ongoing need for improved systems and methods to reduce temperature drift in a DRO.